By Bill Sheets, Herald writer
INDEX — Building a mini-dam on a scenic stretch of the Skykomish River would not cause flooding or reduce water flow, according to preliminary studies by the Snohomish County Public Utility District.
These findings are among the results of studies done recently by the PUD in determining whether to pursue the project.
The utility is looking at building an inflatable mini-dam, or weir, on the river just above Sunset Falls near Index. The PUD believes the project could generate enough power for nearly 10,000 homes. Its cost is estimated at between $110 million and $170 million.
The utility has scheduled open houses for Wednesday in Everett and Thursday in Sultan to discuss its findings with the public.
The meetings will be informal. Visitors may circulate, look at photos and graphics and discuss the idea with officials.
“We heard a lot of concerns from the local residents,” said Kim Moore, an assistant general manager for the PUD. “We’ve been trying to address those concerns.”
Some neighbors and environmental groups oppose any consideration of a dam on the stretch of river.
Jeff Smith, who lives about 50 yards from where the mini-dam would be installed, said the new information makes no difference to him.
“This is not an issue about engineering details,” he said. “This is an issue about a protected natural resource. It’s like negotiating the terms of surrender before the battle starts.”
The south fork of the Skykomish is part of the state’s Scenic Rivers System. Under this designation, development is discouraged but not prohibited.
The river has been listed since 1988 as a protected river by the Northwest Power and Conservation Council, a Portland-based, power-supply planning group.
This designation also does not prevent development, but the Federal Energy Regulatory Commission is required to consider the tag in deciding whether to issue a permit for a dam.
Last year, American Rivers, a national environmental group, listed the stretch of river as the seventh most endangered river in the nation. The designation was prompted by the possible PUD project, said Brett Swift, regional director for the group’s northwest office in Portland.
In the project, water would be diverted from the pooled water behind the weir, above Sunset Falls, through a pipeline downstream to a powerhouse below the falls.
The dam would be inflated only during winter months when the flow is highest, PUD officials have said.
The PUD has a federal permit to study the project but has yet to apply for a license to build. If that occurs, it likely won’t be for three or four more years, Moore said.
Concerns about the project include flooding above the dam and reduced water flow below it; glare from lights; noise and traffic during construction, and the effect on the scenery.
In addition to the findings on flooding and water flow, the PUD also has artist’s conceptions showing the weir would have a minimal effect on the appearance of the river.
Officials have drawn up routes to minimize noise and traffic during construction, Moore said. An electrical switchyard for the power could be hidden behind the powerhouse to keep it invisible from across the river, PUD spokesman Neil Neroutsos said.
Other issues, such as the project’s potential effect on fish, will have to be studied in greater detail, Moore said.
All the information so far is preliminary and will have to be fleshed out further if the utility decides to go ahead with the project, Moore said.
“We have not found, as of yet, a fatal flaw with respect to this project.”
The PUD buys about 90 percent of its power in the form of hydroelectric energy from the Bonneville Power Administration and is looking to diversify.
In 2011, the PUD opened a $29 million mini-dam on Youngs Creek near Sultan. In 2008, the PUD bought a tiny, 6-foot-tall dam and powerhouse on Woods Creek near Monroe from a private utility company for $1.1 million.
The PUD also owns and operates the Jackson Hydroelectric Project on the Sultan River, which includes Culmback Dam on Spada Lake.